The word Gehenna is used only in some translations such as Young’s Literal translation, and in most translations is rendered as Hell.
Matthew 5:29 Young’s literal translation `But, if thy right eye doth cause thee to stumble, pluck it out and cast from thee, for it is good to thee that one of thy members may perish, and not thy whole body be cast to gehenna.
Matthew 5:29 NKJV If your right eye causes you to sin, pluck it out and cast it from you; for it is more profitable for you that one of your members perish, than for your whole body to be cast into hell.
The word in the original Greek is:
So those two words are exactly the same and appear to be a choice by the translator.
The words Sheol, and Hades are both used in several translation:
Hades: Greek used in the New Testament
Sheol: Hebrew used in the Old Testament
Matthew 16:18 And I also say to you that you are Peter, and on this rock I will build My church, and the gates of Hades shall not prevail against it.
Isaiah 38:18 For Sheol cannot thank You, Death cannot praise You; Those who go down to the pit cannot hope for Your truth.
According to Naves topical Bible this is an excerpt:
• The translation of the Hebrew word »sheol,« which signifies the unseen state. Sheol is also translated as »pit,« »lowest pit,« »Sheol,« and »grave« in some versions
Isa 5:14; Isa 14:9; Isa 14:15; Isa 28:15; Isa 28:18; Isa 57:9; Ezek 31:16-17; Ezek 32:21; Ezek 32:27; Amos 9:2; Jonah 2:2; Hab 2:5; Deut 32:22; Ps 86:13; Ps 55:15; 2Sam 22:6; Job 11:8; Job 26:6; Ps 9:17; Ps 16:10; Ps 18:5; Ps 116:3; Ps 139:8; Prov 5:5; Prov 7:27; Prov 9:18; Prov 15:11; Prov 15:24; Prov 23:14; Prov 27:20; Gen 37:35; Gen 42:38; Gen 44:29; Gen 44:31; 1Sam 2:6; 1Kgs 2:6; 1Kgs 2:9; Job 7:9; Job 14:13; Job 17:13; Job 21:13; Job 24:19; Ps 6:5; Ps 30:3; Ps 31:17; Ps 49:14-15; Ps 88:3; Ps 89:48; Ps 141:7; Prov 1:12; Prov 30:16; Eccl 9:10; Song 8:6; Hos 13:14
• The translation of the Greek word »gehenna«
Matt 5:22; Matt 5:29-30; Matt 10:28; Matt 18:9; Matt 23:15; Matt 23:33; Mark 9:43; Mark 9:45; Mark 9:47; Luke 12:5; Jas 3:6
• The translation of the Greek word »hades,« which signifies the unseen world
Matt 11:23; Matt 16:18; Luke 10:15; Luke 16:23; Acts 2:27; Acts 2:31; Rev 1:18; Rev 6:8; Rev 20:13-14
• The future abode of the wicked
Ps 9:17; Prov 5:5; Prov 9:13-18; Prov 15:24; Prov 23:13-14; Isa 30:33; Isa 33:14; Matt 3:12; Matt 5:29-30; Matt 7:13-14; Matt 8:11-12; Matt 10:28; Matt 13:30; Matt 13:38-42; Matt 13:49-50; Matt 16:18; Matt 18:8-9; Matt 18:34-35; Matt 22:13; Matt 25:28-30; Matt 25:41; Matt 25:46; Mark 9:43-48; Luke 3:17; Luke 16:23-26; Luke 16:28; Acts 1:25; 2Thess 1:9; 2Pet 2:4; Jude 1:6; Jude 1:23; Rev 9:1-2; Rev 11:7; Rev 14:10-11; Rev 19:20; Rev 20:10; Rev 20:15; Rev 21:8; Rev 2:11 Wicked, Punishment of
All of these are commonly thought to refer to Hell except the word Sheol as used in the Old Testament, which is most commonly referenced to the grave. The Ancient Hebrew Nation apparently felt that there were two separate places where the dead went. The physical bodies went to grave to decay, but the soul or eternal person could be punished in Hades or what we now call Hell.
Although it is not stated it appears that the grave was a place where righteous people awaited Paradise in sleep, and Hades was a place where the unrighteous were beginning their eternal punishment.
There are some Scriptures which fortify each of these ideas:
John 11:11 through 14 These things He said, and after that He said to them, "Our friend Lazarus sleeps, but I go that I may wake him up." 12 Then His disciples said, "Lord, if he sleeps he will get well." 13 However, Jesus spoke of his death, but they thought that He was speaking about taking rest in sleep. 14 Then Jesus said to them plainly, "Lazarus is dead.
At different times in History all of these words may have had differing connotations, but now they are all considered to be the same place.